Dementia and cognitive decline in general compose one of the most critical challenges of contemporary society. They are both characterised by neuropathological alterations induced by the neurodegenerative nature of the decline [1, 2]. Given the unavailability of effective pharmaceutical treatment, numerous non-pharmacological interventions have been explored in recent years, all of them based on the prospects of neuroplasticity, which refers to the ability of the brain to reorganize its wiring towards optimal cognitive functioning in terms of concentration, attention and memory [3]. Thus, several approaches aim at training certain cognitive functions through cognitive and/or physical training [4, 5]. For example, the Long Lasting Memories – LLM project (www.longlastingmemories.eu, www.llmcare.gr), proposed a combination of computerised physical and cognitive training and demonstrated neuroplastic effects which seem protective against age-related cognitive decline [4, 6, 7]. LLM combined cognitive training of attention, executive functioning and memory with exercises for balance improvement, muscle strengthening, aerobic exercise and flexibility.
The present study aims to compare the aforementioned LLM approaches with traditional dancing and to investigate whether the latter may also be considered as a potential intervention since it combines cognitive and physical training in a more pleasant way [8].
Dance training focuses on coordination and muscle toning, companionship, mental balance, wellness. The rhythm improves the coordination of walking and proprioceptive control of movements in people suffering from neuromuscular and skeletal disorders. Since physiological aging results in cortical atrophy which induces delayed sensory information processing and as a consequence balance loss, our hypothesis is that dance training may be an optimal intervention candidate for improving sensorimotor abilities [9].
The study employed sixty-four elderly people equally divided to an ACTIVE Control group (no physical, but cognitive training only), combined cognitive and physical training (LLM intervention) and a DANCE group. All participants were subjected to a complete neuropsychological and electroencephalographic (EEG) examination both for initial screening and for evaluating the efficacy of each intervention [2, 4].
The EEG examination employed resting state examination and oscillatory analysis based on energy ratios proposed by Moretti et.al. [10]. The markers estimate the theta/gamma and alpha3/alpha2 ratio, which were previously demonstrated to quantify the possibility of future cognitive deterioration due to a non Alzheimer and Alzheimer’s Dementia respectively. The participants were sit on a comfortable, armed chair and were instructed to remain calm with their eyes closed for 5 minutes. The electrical resistances of the electrodes were lower than 2 ΚΩ and the sampling frequency set at 500 Hz. We used a digital Fast Fourier Transform (FFT) to analyze the power spectrum calculated by the power density of brain rhythms with 1 Hz frequency resolution. Then, the frequency bins corresponding to the rhythms under consideration were further analyzed. The analysis focused only on epochs which were artifact-free and of good quality as quantified by an energy-based threshold (theta+alpha energy greater than 60%).
Statistical analysis conducted via a 2 x 3 Mixed Model ANOVA with groups of intervention (ACTIVE, LLM and DANCE) as between-subjects factor and time (pre-post) as within subject factor. Results indicated a statistically significant time by intervention interaction regarding the theta/gamma ratio [F(2,61) = 6.34, p=.003], as well as the alpha3/alpha2 ratio [F(2,61) = 3.20, p=.048]. In addition to that, there was a statistically significant effect of time on the alpha3/alpha2 ratio, [F(1,61) = 8.75, p = .004]. Planned post hoc comparisons of the pre and post intervention results in theta/gamma ratio using paired samples t-tests within the sample of each intervention, although marginal did not yield significance when corrected from multiple comparisons, as the significance level after the multiple comparison correction was set at p = .016 [ACTIVE t(23)=-2.408; p = .024; LLM t(23)=-2.302; p = .031; DANCE t(15)=-.047; p = .963]. A similar result was reached for the alpha3/alpha2 ratio [ACTIVE t(23)=-.305; p = .763; LLM t(23)=1.987; p = .059; DANCE t(15)=2.637; p = .019].
The results, although marginal, point to a specific direction. More specifically, the study implies that regarding the theta/gamma ratio the combination of physical and cognitive training induces more positive effects regarding healthy ageing and reduces the probability for future cognitive deterioration due to dementia in comparison to lack of physical training (ACTIVE group). In contrast, lack of training may lead to cognitive status deterioration and increased danger for dementia progression. Results of the dance intervention additionally lead to the indication that dancing may facilitate preservation of the participant’s cognitive reserve and delay dementia onset.
On the other hand, the results of alpha3/alpha2 ratio direct to an interpretation of: i) a reduction in LLM group, which implies memory improvement and reduced possibility for suffering from Alzheimer’s Disease (AD dementia), ii) an even greater reduction in DANCE group, which implies that traditional dancing may be a robust approach for memory improvement and seems to be the optimal approach for preventing AD onset and iii) a constant situation in ACTIVE group, which means that even a cognitive stimulation program may offer a limited benefit against Alzheimer’s disease. The increase of sample size would help to reach a significant result in the post hoc planned comparisons.
To sum up the aforementioned results demonstrate that both LLM training and traditional dancing could certainly have a potential in shielding against cognitive decline and, therefore, should be further investigated including more participants. Due to their inherent differences it seems that LLM is more suitable for preventing generic cognitive status deterioration, while dancing may be more effective against memory deficits and therefore may be targeted on patients suffering from amnestic Mild Cognitive Impairment (aMCI). Our finding is in accordance with a previous study which demonstrated that physical (aerobic) training increases the hippocampus size and preserves memory function [5]. Therefore, individual cognitive profiles of elderly should be analysed if one were to select the optimal intervention type.